kandi X-RAY | JavaCode Summary
kandi X-RAY | JavaCode Summary
I specifically cover the following topics: Java primitive data types, declaration statements, expression statements, importing class libraries, excepting user input, checking for valid input, catching errors in input, math functions, if statement, relational operators, logical operators, ternary operator, switch statement, and looping. How class variables differ from local variables, Java Exception handling, the difference between run time and checked exceptions, Arrays, and UML Diagrams. Monsters gameboard, Java collection classes, Java ArrayLists, Linked Lists, manipulating Strings and StringBuilders, Polymorphism, Inheritance, Protected, Final, Instanceof, interfaces, abstract classes, abstract methods. You need interfaces and abstract classes because Java doesn't allow you to inherit from more than one other class. Java threads, Regular Expressions, Graphical User Interfaces (GUI) using Java Swing and its components, GUI Event Handling, ChangeListener, JOptionPane, combo boxes, list boxes, JLists, DefaultListModel, using JScrollpane with JList, JSpinner, JTree, Flow, Border, and Box Layout Managers. Created a calculator layout with Java Swing's GridLayout, GridBagLayout, GridBagConstraints, Font, and Insets. JLabel, JTextField, JComboBox, JSpinner, JSlider, JRadioButton, ButtonGroup, JCheckBox, JTextArea, JScrollPane, ChangeListener, pack, create and delete files and directories. How to pull lists of files from directories and manipulate them, write to and read character streams from files. PrintWriter, BufferedWriter, FileWriter, BufferedReader, FileReader, common file exceptions Binary Streams - DataOutputStream, FileOutputStream, BufferedOutputStream, all of the reading and writing primitive type methods, setup Java JDBC in Eclipse, connect to a MySQL database, query it and get the results of a query. JTables, JEditorPane Swing component. HyperlinkEvent and HyperlinkListener. Java JApplet, Java Servlets with Tomcat, GET and POST methods, Java Server Pages, parsing XML with Java, Java XPath, JDOM2 library, and 2D graphics. *Created a Java Paint Application using swing, events, mouse events, Graphics2D, ArrayList *Designed a Java Video Game like Asteroids with collision detection and shooting torpedos which also played sound in a JFrame, and removed items from the screen when they were destroyed. Rotating polygons, and Making Java Executable. Model View Controller (MVC) The Model is the class that contains the data and the methods needed to use the data. The View is the interface. The Controller coordinates interactions between the Model and View. DESIGN PATTERNS: Strategy design patternis used if you need to dynamically change an algorithm used by an object at run time. The pattern also allows you to eliminate code duplication. It separates behavior from super and subclasses. The Observer pattern is a software design pattern in which an object, called the subject (Publisher), maintains a list of its dependents, called observers (Subscribers), and notifies them automatically of any state changes, usually by calling one of their methods. The Factory design pattern is used when you want to define the class of an object at runtime. It also allows you to encapsulate object creation so that you can keep all object creation code in one place The Abstract Factory Design Pattern is like a factory, but everything is encapsulated. The Singleton pattern is used when you want to eliminate the option of instantiating more than one object. (Scrabble letters app) The Builder Design Pattern is used when you want to have many classes help in the creation of an object. By having different classes build the object you can then easily create many different types of objects without being forced to rewrite code. The Builder pattern provides a different way to make complex objects like you'd make using the Abstract Factory design pattern. The Prototype design pattern is used for creating new objects (instances) by cloning (copying) other objects. It allows for the adding of any subclass instance of a known super class at run time. It is used when there are numerous potential classes that you want to only use if needed at runtime. The major benefit of using the Prototype pattern is that it reduces the need for creating potentially unneeded subclasses. Java Reflection is an API and it's used to manipulate classes and everything in a class including fields, methods, constructors, private data, etc. (TestingReflection.java) The Decorator allows you to modify an object dynamically. You would use it when you want the capabilities of inheritance with subclasses, but you need to add functionality at run time. It is more flexible than inheritance. The Decorator Design Pattern simplifies code because you add functionality using many simple classes. Also, rather than rewrite old code you can extend it with new code and that is always good. (Pizza app) The Command design pattern allows you to store a list of commands for later use. With it you can store multiple commands in a class to use over and over. (ElectronicDevice app) The Adapter pattern is used when you want to translate one interface of a class into another interface. Allows 2 incompatible interfaces to work together. It allows the use of the available interface and the target interface. Any class can work together as long as the Adapter solves the issue that all classes must implement every method defined by the shared interface. (EnemyAttacker app) The Facade pattern basically says that you should simplify your methods so that much of what is done is in the background. In technical terms you should decouple the client from the sub components needed to perform an operation. (Bank app) The Bridge Pattern is used to decouple an abstraction from its implementation so that the two can vary independently. Progressively adding functionality while separating out major differences using abstract classes. (EntertainmentDevice app) In a Template Method pattern, you define a method (algorithm) in an abstract class. It contains both abstract methods and non-abstract methods. The subclasses that extend this abstract class then override those methods that don't make sense for them to use in the default way. (Sandwich app) The Iterator pattern provides you with a uniform way to access different collections of Objects. You can also write polymorphic code because you can refer to each collection of objects because they'll implement the same interface. (SongIterator app) The Composite design pattern is used to structure data into its individual parts as well as represent the inner workings of every part of a larger object. The composite pattern also allows you to treat both groups of parts in the same way as you treat the parts polymorphically. You can structure data, or represent the inner working of every part of a whole object individually. (SongComponent app) The flyweight design pattern is used to dramatically increase the speed of your code when you are using many similar objects. To reduce memory usage the flyweight design pattern shares Objects that are the same rather than creating new ones. (FlyWeightTest app) State Pattern allows an object to alter its behavior when its internal state changes. The object will appear to change its class. (ATMState) The Proxy design pattern limits access to just the methods you want made accessible in another class. It can be used for security reasons, because an Object is intensive to create, or is accessed from a remote location. You can think of it as a gate keeper that blocks access to another Object. (TestATMMachine) The Chain of Responsibility pattern has a group of objects that are expected to between them be able to solve a problem. If the first Object can't solve it, it passes the data to the next Object in the chain. (TestCalcChain) The Interpreter pattern is used to convert one representation of data into another. The context cantains the information that will be interpreted. The expression is an abstract class that defines all the methods needed to perform the different conversions. The terminal or concrete expressions provide specific conversions on different types of data. (MeasurementConversion) The Mediator design pattern is used to handle communication between related objects (Colleagues). All communication is handled by a Mediator Object and the Colleagues don't need to know anything about each other to work together. (TestStockMediator) The Memento design pattern provides a way to store previous states of an Object easily. It has 3 main classes: 1) Memento: The basic object that is stored in different states. 2) Originator: Sets and Gets values from the currently targeted Memento. Creates new Mementos and assigns current values to them. 3) Caretaker: Holds an ArrayList that contains all previous versions of the Memento. It can store and retrieve stored Mementos. (TestMemento) The Visitor design pattern allows you to add methods to classes of different types without much altering to those classes. You can make completely different methods depending on the class used with this pattern. (VisitorTest).
Top functions reviewed by kandi - BETA
- Draw this game
- Move the ship rectangle to a ship rectangle .
- Initialize the radio buttons .
- Move a monster to another
- Sets the favorite character .
- Writes the XML to the database .
- Writes the info to a file
- Add one or more Threads to the pool
- This example is used for testing
- Gets the element with the given element name and attrName .
JavaCode Key Features
JavaCode Examples and Code Snippets
Trending Discussions on JavaCode
I have this code...
ANSWERAnswered 2022-Mar-08 at 14:19
You may be overwriting an existing file, change to use truncate as well which will reset the file size to zero:
I'm new to spark and my understanding is this:
- jars are like a bundle of java code files
- Each library that I install that internally uses spark (or pyspark) has its own jar files that need to be available with both driver and executors in order for them to execute the package API calls that the user interacts with. These jar files are like the backend code for those API calls
- Why are these jar files needed. Why could it not have sufficed to have all the code in python? (I guess the answer is that originally Spark is written in scala and there it distributes its dependencies as jars. So to not have to create that codebase mountain again, the python libraries just call that javacode in python interpreter through some converter that converts java code to equivalent python code. Please if I have understood right)
- You specify these jar files locations while creating the spark context via
spark.executor.extraClassPath. These are outdated parameters though I guess. What is the recent way to specify these jar files location?
- Where do I find these jars for each library that I install? For example synapseml. What is the general idea about where the jar files for a package are located? Why do not the libraries make it clear where their specific jar files are going to be?
I understand I might not be making sense here and what I have mentioned above is partly just my hunch that that is how it must be happening.
So, can you please help me understand this whole business with jars and how to find and specify them?...
ANSWERAnswered 2021-Dec-09 at 12:15
Each library that I install that internally uses spark (or pyspark) has its own jar files
Can you tell which library are you trying to install ?
Yes, external libraries can have jars even if you are writing code in python.
These libraries must be using some UDF (User Defined Functions). Spark runs the code in java runtime. If these UDF are written in python, then there will be lot of serialization and deserialization time due to converting data into something readable by python.
Java and Scala UDFs are usually faster that's why some libraries ship with jars.
Why could it not have sufficed to have all the code in python?
Same reason, scala/java UDFs are faster than python UDF.
What is the recent way to specify these jar files location?
You can use
spark.jars.packages property. It will copy to both driver and executor.
Where do I find these jars for each library that I install? For example synapseml. What is the general idea about where the jar files for a package are located?
They have mentioned here what jars are required i.e.
I try to upgrade our application to Java 17. but it seems have some problem:
org.mybatis.spring.MyBatisSystemException: nested exception is org.apache.ibatis.exceptions.PersistenceException:Error querying database. Cause: java.lang.reflect.InaccessibleObjectException: Unable to make public int java.util.Collections$EmptyList.size() accessible: module java.base does not "opens java.util" to unnamed module @33b37288 Cause: java.lang.reflect.InaccessibleObjectException: Unable to make public int java.util.Collections$EmptyList.size() accessible: module java.base does not "opens java.util" to unnamed module @33b37288 ...
ANSWERAnswered 2022-Jan-09 at 07:13
isEmpty(), you can use the pseudo-properties instead of the method.
I am trying to send a jsonArray from my javacode to my nodeJS application, but i keep getting this error on my nodejs side, which i have trouble understanding why this is? As sending a normal JSONObject works fine. Any help would be greatly appreciated!...
ANSWERAnswered 2021-Sep-15 at 12:37
Json is invalid.
- It should be wrapped as an object
- keys have to be wrapped with double quetes
- key cannot appeared more then one occurrence in same object.
=symbol not valid in json and you have to to separate between key and value with
There is such a need to detect whether the jvm code in the container has been maliciously modified. I google some related questions, and We can dynamically monitor jvm through Java Instrumentation. But I failed in the first step, I cannot get the jvm in the container. If it was host jvm, it will be ok.
ANSWERAnswered 2021-May-10 at 14:01
JDK 8 is not namespace aware and thus cannot attach to a JVM process in a different mount namespace (i.e. container).
Attach API has been fixed to work with containers in JDK 10.
Meanwhile there is jattach project that fixes the problem.
jattach allows to connect to any HotSpot JVM in a container (including JDK 8 and even older JDKs) even with no JDK installed on the host (this is a tiny program in pure C). You can use
jattach in place of Java Attach API to do anything:
- load Java agent;
- get thread dumps and heap dumps;
jcmdcommand, and more.
I'm trying to map a structure which contains an array of structure in JNA. The size of the embedded structure is not defined in advanced in the C++ declaration of the structure but in the java code. My issue is that I get Exception in thread "main" java.lang.Error: Invalid memory access
The C++ header file is as follows :...
ANSWERAnswered 2021-Mar-30 at 16:34
Can you consider following data structure?
I want to save this java code snippet to a file (Demo.java) using PowerShell script in Jupyterlab:
ANSWERAnswered 2021-Jan-11 at 23:30
\"...\"to enclose the entire argument passed to
`\"...`\"to enclose the string embedded in that argument.
I try to implement a BottomNavigationMenu in my app using the Jetpack navigation. I followed each step of this tutorial https://www.youtube.com/watch?v=pT_4rV3gO78 but unfortunately I could not integrate into my app and I get an error when starting the app...
ANSWERAnswered 2021-Jan-10 at 12:25
there are a few things off in my eyes
-I don't think it's the issue but for data binding, you need to wrap your XML file in
attribute I guess you just didn't put it here but if that's the case fix it.
-you need to be sure that your menu item id witch is FR_LanguageSelection here be the same as your destination fragment id
-you need to navigate using actions that are declared in your nav_graph but there is nothing here
check these and if these are not the case let me know
Hey I'm currently writing a Java application that accesses NEO4J via Spring Neo4J Driver.
I have a couple of nodes with arrays. No I'm trying to write an cypher Query that deletes an Element from an array of a matched node. If the element was the last one i would love to delete the complete node. To achive this I'm using
apoc.do.when. You can find a simplified version of my query below.
ANSWERAnswered 2020-Nov-13 at 21:08
You can modify the Cypher query to return a result that indicates whether an update or deletion occurred. For example:
I was doing activity where I had to save some values in the Shared Preferences but this activity would not open now. In this problem it's showing zero errors in my code so I am not able to understand where and what to be modified
ANSWERAnswered 2020-Oct-08 at 15:06
You're supposed to initialize the
SharedPreferences instance in the
onCreate() method, since the context is not attached to your activity yet (until it reaches
No vulnerabilities reported
You can use JavaCode like any standard Java library. Please include the the jar files in your classpath. You can also use any IDE and you can run and debug the JavaCode component as you would do with any other Java program. Best practice is to use a build tool that supports dependency management such as Maven or Gradle. For Maven installation, please refer maven.apache.org. For Gradle installation, please refer gradle.org .
Reuse Trending Solutions
Subscribe to our newsletter for trending solutions and developer bootcamps
Share this Page